In the last years of Augustus the Strong's life, Brühl's political career began. After he had shown his organisational talent at the Zeithain camp, a gigantic army show, he took over key positions at court. From 1731 he was Director General of Excise and thus responsible for the collection of excise duties. From 1732 he was in charge of the entire financial administration. The young Elector Frederick Augustus II (as King of Poland Augustus III), who succeeded Augustus the Strong in 1733, trusted Brühl and entrusted him with further tasks. Brühl became a cabinet minister and had been second in command to the king since the ousting of Count Alexander Sulkovsky. The appointment as prime minister, which took place in 1746, was only a formality.
Brühl organised a European power alliance against the Kingdom of Prussia. However, Frederick II of Prussia occupied neighbouring Saxony and held his own against all opponents in the Seven Years' War, causing Brühl's long-term foreign policy concept to fail. With the Peace of Hubertusburg in 1763, Saxony left the circle of the great European powers. Had Brühl's coalition won, which was entirely possible and only failed due to coincidences, Prussia would not have risen to become the dominant military power that spread like an oil slick across the map in the 19th century and eventually absorbed all of Germany.